Low power radiofrequency (rf) communication systems for secure wireless patch initialization and methods of use

ABSTRACT

Provided herein is a wireless healthcare system comprising at least one sensor and a base unit adaptable to be in communication with the sensor. The sensor can be is adaptable to communicate with the base unit at a first power during formation of a communication link and is further adaptable to communicate with the base unit at a second power after the communication link has been formed, and wherein the sensor and base unit are components of a wireless healthcare system. The sensor can be a patch adaptable to be positioned on the surface of a patient. Further provided herein is a method of using the wireless healthcare system and kit.

CROSS-REFERENCE

This application claims the benefit of U.S. Provisional Application No.60/982,225, filed Oct. 24, 2007, which application is incorporatedherein by reference in its entirety.

BACKGROUND OF THE INVENTION

Wireless healthcare systems are being increasingly used to help reducehealthcare cost, increase patient independence and provide betteroutcomes. A typical wireless healthcare system includes sensors, a hostdevice or relay station, and a remote server. The sensors typicallysense physiological signals from the body and wirelessly transmit themto a nearby host device or relay station. The host device receives thesignals from the sensors and can then process and relay them to theremote server. The signal can be relayed using a cellular or othersuitable type of network.

One critical aspect of remote monitoring of human physiological signalsis to ensure that the privacy of the patient is maintained. Wirelesstransmission of these physiological signals needs to be protectedagainst unauthorized detection of the signals. One method that can beused to ensure that patient information remains confidential includesencrypting data transmission with a 128-bit or better advancedencryption standard (AES) encryption scheme. Such a scheme involvessharing of private keys between the wireless patches and the host deviceprior to transmission. In order to accomplish this, sharing of privatekeys between the wireless patches and the host device prior totransmission can be done. This is feasible when the sensors and the hostdevice could be purchased by patients at the same time, and also thehost device could be reused with the same patch at different times.Another method is to ensure private key exchange by allowing the hostdevice to program the keys into the sensors using near fieldcommunication so that nearby detectors cannot listen to thetransmissions as the near field communication's range is only about 20cm. Such a method can be used when it is practical to have an additionalwireless method (magnetic field induction using 13.56 MHz bandwidth)that is different from the ones used by the wireless healthcare systems(radio frequency (RF) bands in the hundreds of MHz and in GHz) in thewireless patches and host device.

Therefore, a wireless healthcare system that is capable of eliminatingdetection of patient information by devices external to the system byoperating at a low-power RF mode during the key-exchange period would beuseful.

SUMMARY OF THE INVENTION

1. Provided herein is a wireless healthcare system comprising at leastone sensor and a base unit adaptable to be in communication with thesensor in a wireless healthcare system. The sensor can be adaptable tocommunicate with the base unit at a first power during formation of acommunication link. In some embodiments, the sensor can be in wirelesscommunication with the base unit. The sensor can be further adaptable tocommunicate with the base unit at a second power after the communicationlink has been formed between the base unit and the sensor. The sensorcan be a patch. In some embodiments, the patch can be positioned on thesurface of a patient. The sensor can be adaptable to communicate withthe base unit at a first power, where the first power is a low powermode. Additionally, the wireless healthcare system can comprise a sensoradaptable to sense, detect, measure, and/or monitor at least onephysiological parameter from a patient. Furthermore, the wirelesshealthcare system can be in communication with a network server. In someembodiments, the wireless healthcare system can be in wirelesscommunication with a network server. The wireless healthcare system canfurther comprise more than one sensor. The base unit can furthercomprise a power-amplifier. In some embodiments, the wireless healthcaresystem comprises a base unit wherein the base unit is adaptable toselect a first power output level of −25 dBm (Decibel referenced tomilliwatt) for the power amplifier and is further adaptable to attenuatethe output signal by another 60 dB (Decibel). Furthermore, the base unitcan further comprise an antenna. In some embodiments, the antenna can beadaptable to transmit power during the initialization phase from about−60 dBm to about −100 dBm. In some embodiments, the antenna can beadaptable to transmit power during the initialization phase of about −85dBm. The sensor can also comprise a power-amplifier. The sensor can beadaptable to select a first power level output level of −25 dBm for thepower amplifier and is further adaptable to attenuate the output signalby another 60 dB. The sensor can also comprise an antenna adaptable totransmit power during the initialization phase of about −85 dBm.

Further provided herein is a method for encrypting data sent between abase unit and at least one sensor of a wireless healthcare systemcomprising: bringing the at least one sensor of the wireless healthcaresystem proximate to the base unit of the wireless healthcare system whena communication link between base unit and the sensor is in low powermode; establishing an encrypted link between the sensor and the baseunit; and increasing the power level to a higher power after theencrypted link has been formed between the sensor and the base unit. Insome embodiments of the method, the wireless healthcare system comprisesmore than one sensor. The method can further comprise the step ofestablishing an encrypted link between the base and the more than onesensor. The method can further comprise transmitting patient informationfrom the sensor to the base unit. The establishing step can furthercomprise selecting an initial low power level and attenuating the outputlevel. In some embodiments of the method, the establishing step of themethod can further comprise the steps of: (a) sending a beacon from thebase unit to the at least one sensor to establish the communicationlink; (b) receiving the beacon with the at least one sensor; (c) sendinga key continuously from the at least one sensor; (d) receiving the keywith the base unit; (e) sending the key from the base unit to the atleast one sensor; (f) receiving the key with the at least one sensor andnotifying the base unit to encrypt the communication link; and (g)receiving the notification from the base unit and switching the baseunit from the at least one sensor communication link to the encryptedlink. The key can be selected from a phone number, retinal scan, fingerprint, or any other suitable biometric information, or combinationthereof. The method provided herein can further comprise the step oftransmitting patient information to a network server.

Further provided herein are kits for transmitting sensitivephysiological data from a patient to a host device comprising at leastone sensor adaptable to be positioned on a patient and a base unit incommunication with the at least one sensor, wherein the sensor isadaptable to communicate with the base unit at a first power duringformation of a communication link and is further adaptable tocommunicate with the base unit at a second power after the communicationlink has been formed, and wherein the sensor and base unit arecomponents of a wireless healthcare system. The kit can comprise morethan one sensor.

INCORPORATION BY REFERENCE

All publications, patents, and patent applications mentioned in thisspecification are herein incorporated by reference to the same extent asif each individual publication, patent, or patent application wasspecifically and individually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1 illustrates one embodiment of a wireless healthcare system; and

FIG. 2 illustrates the components of one embodiment of a low power-RFtransmitter and one embodiment of a receiver.

DETAILED DESCRIPTION OF THE INVENTION

Provided herein is a wireless healthcare system comprising at least onesensor and a base unit adaptable to be in communication with the sensorin a wireless healthcare system. The sensor can be adaptable tocommunicate with the base unit at a first power during formation of acommunication link. In some embodiments, the sensor can be in wirelesscommunication with the base unit. The sensor can be further adaptable tocommunicate with the base unit at a second power after the communicationlink has been formed between the base unit and the sensor. The sensorcan be a patch. In some embodiments, the patch can be positioned on thesurface of a patient. The sensor can be a wearable garment wearable bythe patient that can detect signals from the patient. The sensor can beadaptable to communicate with the base unit at a first power, where thefirst power is a low power mode. Additionally, the wireless healthcaresystem can comprise a sensor adaptable to sense, detect, measure, and/ormonitor at least one physiological parameter from a patient.Furthermore, the wireless healthcare system can be in communication witha network server. In some embodiments, the wireless healthcare systemcan be in wireless communication with a network server. The wirelesshealthcare system can further comprise more than one sensor. The baseunit can further comprise a power-amplifier. In some embodiments, thewireless healthcare system comprises a base unit wherein the base unitis adaptable to select a first power output level of −25 dBm for thepower amplifier and is further adaptable to attenuate the output signalby another 60 dB. Furthermore, the base unit can further comprise anantenna. In some embodiments, the antenna can be adaptable to transmitpower during the initialization phase from about −60 dBm to about −100dBm. In some embodiments, the antenna can be adaptable to transmit powerduring the initialization phase of about −85 dBm. The sensor can alsocomprise a power-amplifier. The sensor can be adaptable to select afirst power level output level of −25 dBm for the power amplifier and isfurther adaptable to attenuate the output signal by another 60 dB. Thesensor can also comprise an antenna adaptable to transmit power duringthe initialization phase of about −85 dBm.

I. Systems

Provided herein is a wireless healthcare system for use in transmittingpatient information in a secure fashion using a wireless communicationdevice. The device provided herein includes a sensor for transmitting asignal to a base unit using a key-exchange program to encrypt thesignal, thereby preventing devices external to the system, but in rangeof the signal, from detecting the signal transmitted between the sensorand the base unit. For a wireless healthcare system to be used forprivate key exchange, the radio radiofrequency (RF) power of the baseunit transmitter needs to be reduced close to the sensitivity of thewireless sensor receiver so that the transmitter and receiver could bebrought close to each other and still maintain a wireless link. Anadditional external electrical device not part of the system but capableof detecting the electrical signal between the sensor and base unit, oreavesdropping, positioned one meter away from the system will onlydetect a signal significantly below the receiver sensitivity. Forexample purposes only, an external device near the system describedherein will detect a signal with at least a 40 dB of free space loss,making reception by the external device nearly impossible.

In some embodiments, the initial placement of the patches on the humanbody is followed by a wireless initialization sequence at very low powerby bringing the base unit and the sensor in proximity to each other.Normal data transmission of a signal from the sensors from the sensorsto the base unit can then occur following the initialization at normalpower-level and range of operation. This ability to bring the sensorsand the base unit close to each other distinguishes the wirelesshealthcare system from a generic wireless network where bringing thesensor and the base unit in close proximity might not be possible. Theability to bring the sensor and base unit close together can simplifythe complexity and operation of the system, and can reduce the cost ofthe system.

FIG. 1 illustrates one embodiment of a wireless healthcare system. Thewireless healthcare system can comprise at least one sensor and a baseunit. In some embodiments, multiple sensors are used. The sensor can bepositioned on a patient as shown in FIG. 1. The sensor can be a wirelesssensor. Alternatively, the sensor can be in the form of a patch.Alternatively, the sensor can be in the form of a wearable garment. Thesensor can be a wired sensor, where the sensor is wired to a base unit.In some embodiments, the sensor can be a wireless sensor in wirelesscommunication with the base unit. When the sensor is ready for use, thesensor can be powered up. During the power up processes, the sensorundergoes a boot-up process. During this time, an attempt can be made toform a connection between the sensor and the base unit. The sensor canwait to receive commands from the base unit to establish wireless linkparameters to transmit data. In order to establish a wireless link, thesensor either listens in a predetermined “broadcast channel” oralternatively, the sensor can scan multiple channels where the hostdevice may be transmitting beacons for the sensor. In some embodiments,the sensor itself could give an indication that the sensor is ready tobe initialized. The patch or wearable item could also give an indicationthat the sensor is ready to be initialized. The sensor can give an audioindication that the sensor is ready to be initialized. Alternatively,the sensor can give a visual indication that the sensor is ready to beinitialized.

The base unit can be a component of a host system. Alternatively thebase unit can be a stand alone unit in communication with the sensor.FIG. 2 illustrates one embodiment of a sensor and base unit. The sensorin FIG. 2 has a sensitivity of −90 dBm. A receiver signal strength of−85 dBm is assumed to result in virtually error-free data receptionduring the initialization process. Any suitable signal and sensitivitylevel that results in error-free operation can be used.

Once the sensor has given an indication that the sensor is ready to beinitialized, the end-user can then start the initialization process bybringing the base unit close to the wireless sensor. Alternatively, thewireless sensor can be brought close to the base unit. The sensor can bepositioned within about 15 cm of the base unit. Additionally, the sensorcan be positioned within about 10 cm of the base unit. The sensor can bepositioned within about 5 cm of the base unit. In some embodiments, thesensor can be positioned within about 2 cm of the base unit.

The initialization process can then be started by the end-user. The baseunit can select a low initialization power level of −25 dBm for theinternal/external power-amplifier (PA) to send commands to the wirelesspatch to be initiated. The base unit can then further attenuate theoutput signal by another 60 dB by switching to an RF path that includesa 60 dB attenuator. This results in a −85 dBm radiated power at thetransmit antenna. In some embodiments, the power radiated from antennacan range between about −60 dBm and −100 dBm. The close proximity of thesensor to the base unit can allow the sensor to receive the signal fromthe base unit reliably. The sensor can also verify that the signal isreceived error-free. In some embodiments, the signal can be checked foralteration using a cyclic redundancy check (CRC) of the received datapacket. The sensor can then compare the signal after the CRC to thesignal at the beginning of the initialization sequence. If the CRCfails, the sensor can ignore the signal from the base unit. Noconnection between the base unit and the sensor is formed and the sensorstays in listening mode.

The system provided herein can be a static system that establishes alink between the base and the sensor at one distance using one lowerpower. In some embodiments, the system can comprise a system that can beadjusted. For example, in some cases a higher complexity eavesdroppingreceiver with extremely low sensitivity can be in proximity to thesystem wherein the eavesdropping receiver can detect and demodulatetransmissions at power as low as −185 dBm. The system could then lowerthe power transmission level to a lower level. Additionally, the baseunit can be brought into closer proximity to the sensor. Using an evenlower power level but having the sensor and base unit in closerproximity can help to maintain a reliable wireless link between the baseunit and sensor at such low power levels.

Provided herein is one embodiment of a key-exchange program for sendingencrypted data in order to establish a connection between the sensor andthe base unit. The key-exchange program can comprise the base unitcontinuously sending out a beacon to be detected by the sensor. Thewireless sensor can receive the beacon from the base unit, therebyestablishing a preliminary connection between the base unit and thesensor. The sensor can then send out a key (information or a parameterthat determines the functional output of a cryptic algorithm)continuously to the base unit. The base unit then receives the key fromthe sensor and then sends the key continuously back to the sensor. Afterreceiving the key, the sensor sends continuous notification to the baseunit that it is permissible to switch to the encrypted channel. Thesensor then listens for a signal from the base unit on the encryptedchannel. The base unit can then receive the switching message from thesensor and switches to the encrypted channel. In some embodiments, thewireless sensor can send acknowledgments or other capability parametermessages to the base unit using a similar low-power mode fortransmission to the host device. Together, the host device and thewireless patch can exchange encryption key information at power levelsnot detectable by eavesdroppers or other external devices that arewithin range and are of similar setup.

After the key-exchange between the sensor and the base unit is complete,the sensor and base unit can communicate reliably with each other toestablish and complete the initialization process. Any signal receivedby an eavesdropping device at this point suffers an additional 40 dBfree-space path-loss (−135 dBm) or more, even at one meter distancesfrom the base unit. This reduction in free-space path-loss can make itvirtually impossible for an eavesdropping device to detect anddemodulate the transmission signal between the sensor and the base-unit.Any similar signal attenuation mechanism can be used to achievelow-power transmissions. For example purposes only, differentcombinations of power amplified power and one or more attenuator stagescould be used to achieve the desired power level. The initializationsequence can also be modified to follow near field communication (NFC)Forum's technical specifications. In some embodiments, an NFCtransceiver can be employed in addition to a radiofrequency (RF)transceiver which would use the same RF antenna. In this case, the RFantenna tuned for RF frequencies can provide the adequate attenuation atthe NFC frequency providing the desired privacy.

Additionally, any subsequent (periodic) key exchange for enhancedprivacy does not need to involve low-power transmissions, as they canuse the existing keys to encrypt the transmitted data containing the newkeys. The key can also be the unique identification of the end-userincluding, but not limited to, the end user's mobile phone number, orany suitable biometric information such as finger-print, or retinalscan.

In some embodiments, multiple sensors can be used. The sameauthentication key can be used by the base unit in conjunction withmultiple sensors that are in close proximity to each other. By issuing asingle command on the host device, the end user needs to initiate theauthentication process once. The base unit can then go through the aboveprocedure with each wireless patch to authenticate all of the remainingsensors. This eliminates the need to authenticate all the sensorsseparately.

Once the initialization is completed successfully, subsequenttransmissions between the base unit and the sensor can be encrypted. Thetransmit power levels are restored to normal levels by switching tohigher power-levels of the power-amplifier, as well as bypassing the RFpath with the 60 dB attenuation.

In some embodiments, the system can be adaptable to upload informationfrom the base unit onto a network server. The base unit can behard-wired to the network server. Alternatively the base unit can bewirelessly connected to the network server.

II. Methods

Further provided herein is a method for encrypting data sent between abase unit and at least one sensor of a wireless healthcare systemcomprising: bringing the at least one sensor of the wireless healthcaresystem proximate to the base unit of the wireless healthcare system whena communication link between base unit and the sensor is in low powermode; establishing an encrypted link between the sensor and the baseunit; and increasing the power level to a higher power after theencrypted link has been formed between the sensor and the base unit. Insome embodiments of the method, the wireless healthcare system comprisesmore than one sensor. The method can further comprise the step ofestablishing an encrypted link between the base and the more thansensor. The method can further comprise transmitting patient informationfrom the sensor to the base unit. The establishing step can furthercomprise selecting an initial low power level and attenuating the outputlevel. In some embodiments of the method, the establishing step of themethod can further comprise the steps of: (a) sending a beacon from thebase unit to the at least one sensor to establish the communicationlink; (b) receiving the beacon with the at least one sensor; (c) sendinga key continuously from the at least one sensor; (d) receiving the keywith the base unit; (e) sending the key from the base unit to the atleast one sensor; (f) receiving the key with the at least one sensor andnotifying the base unit to encrypt the communication link; and (g)receiving the notification from the base unit and switching the baseunit from the at least one sensor communication link to the encryptedlink. The key can be selected from a phone number, retinal scan, fingerprint, or any other suitable biometric information, or combinationthereof. The method provided herein can further comprise the step oftransmitting patient information to a network server.

III. Kits

Further provided herein are kits for transmitting sensitivephysiological data from a patient to a host device comprising: at leastone sensor adaptable to be positioned on a patient; and a base unit incommunication with the at least one sensor, wherein the sensor isadaptable to communicate with the base unit at a first power duringformation of a communication link and is further adaptable tocommunicate with the base unit at a second power after the communicationlink has been formed, and wherein the sensor and base unit arecomponents of a wireless healthcare system. The kit can comprise morethan one sensor.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention. It is intended thatthe following claims define the scope of the invention and that methodsand structures within the scope of these claims and their equivalents becovered thereby.

1. A wireless healthcare system comprising: at least one sensor; and abase unit adaptable to be in communication with the sensor, wherein thesensor is adaptable to communicate with the base unit at a first powerduring formation of a communication link and is further adaptable tocommunicate with the base unit at a second power after the communicationlink has been formed, and wherein the sensor and base unit arecomponents of a wireless healthcare system.
 2. The wireless healthcaresystem of claim 1 wherein the sensor is a patch adaptable to bepositioned on the surface of a patient.
 3. The wireless healthcaresystem of claim 1 wherein the first power is a low power mode.
 4. Thewireless healthcare system of claim 1 wherein the sensor is adaptable todetect at least one physiological parameter from a patient.
 5. Thewireless healthcare system of claim 1 wherein the base unit is furtheradaptable to be in external communication with a network server.
 6. Thewireless healthcare system of claim 1 wherein the base unit is adaptableto be in wireless communication with the sensor.
 7. The wirelesshealthcare system of claim 1 further comprising more than one sensor. 8.The wireless healthcare system of claim 1 wherein the base unit furthercomprises a power-amplifier.
 9. The wireless healthcare system of claim1 wherein the base unit is adaptable to select a first power leveloutput level of −25 dBm for the power amplifier and is further adaptableto attenuate the output signal by another 60 dB.
 10. The wirelesshealthcare system of claim 1 wherein the base unit further comprises anantenna.
 11. The wireless healthcare system of claim 10 wherein theantenna is adaptable to transmit power during the initialization phaseof about −85 dBm.
 12. The wireless healthcare system of claim 1 whereinthe sensor further comprises a power-amplifier.
 13. The wirelesshealthcare system of claim 1 wherein the sensor is adaptable to select afirst power level output level of −25 dBm for the power amplifier and isfurther adaptable to attenuate the output signal by another 60 dB. 14.The wireless healthcare system of claim 1 wherein the sensor furthercomprises an antenna.
 15. The wireless healthcare system of claim 14wherein the antenna is adaptable to transmit power during theinitialization phase of about −85 dBm.
 16. A method for encrypting datasent between a base unit and at least one sensor of a wirelesshealthcare system comprising: (a) bringing the at least one sensor ofthe wireless healthcare system proximate to the base unit of thewireless healthcare system when the communication link is in lower powermode; (b) establishing an encrypted link between the sensor and the baseunit; and (c) increasing the power level to a higher power after thelink has been formed between the sensor and base unit.
 17. The method ofclaim 16 wherein the healthcare systems further comprises more than onesensor.
 18. The method of claim 16 further comprising the step ofestablishing an encrypted link between the base and the more than onesensor.
 19. The method of claim 16 further comprising the step oftransmitting patient information from the sensor to the base unit. 20.The method of claim 16 wherein the establishing step comprises selectingan initial low power level and attenuating the output level.
 21. Themethod of claim 16 wherein the establishing step further comprises thesteps of: (a) sending a beacon from the base unit to the at least onesensor to establish a communication channel; (b) receiving the beaconwith the at least one sensor; (c) sending a key continuously from the atleast one sensor; (d) receiving the key with the base unit; (e) sendingthe key from the base unit to the at least one sensor; (f) receiving thekey with the at least one sensor and notifying the base unit to encryptthe communication channel; and (g) receiving the notification from thebase unit and switching the base unit to the at least one sensorcommunication link to the encrypted link.
 22. The method of claim 21wherein the key is selected from at least one of a phone number, retinalscan, fingerprint, or biometric information.
 23. The method of claim 21further comprising the step of transmitting patient information to anetwork server.
 24. A kit for transmitting sensitive physiological datafrom a patient to a host device comprising: (h) at least on sensoradaptable to be positioned on a patient; and (i) a base unit incommunication with the at least one sensor, wherein the sensor isadaptable to communicate with the base unit at a first power duringformation of a communication link and is further adaptable tocommunicate with the base unit at a second power after the communicationlink has been formed, and wherein the sensor and base unit arecomponents of a wireless healthcare system.
 25. The kit of claim 24further comprising more than one sensor.